The 3-way, 2 position valves are pilot operated, and designed for high flow applications. The 3-way valve is available in following sizes: ¼” (fig. 1 and 2), ½” (fig. 3), 1” (fig. 4 and 5), 1 ½”(fig. 6) and 2”(fig. 7). The STI 3-way valve can be used in one or more synchronous units piloted by a pneumatic pressure switch in order to achieve the function of a lock up device.